Valve eor rock drills



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June 2, 1931. w. A. SMITH. 5R, ET AL VALVE FOR ROCK DRILLS Filed Sept.'7, 1928 a WW? 7 \T/ J0 d y fie j %V L zy u K m. H 1\|\\|l ww w \fiwu.aZ M fif s p FE. Ev A c d ym A Patented June 2, 1931 UNITED STATESPATENT? OFFICE WILLIAM A. SMITH, SR, AND WILLIAM A. SMITH, an,QFPHILLIPSBUR I W JERSEY,

ASSIGNORS r0 INeERsoLL-RANn COMPANY, or JERSEY our, new JERSEY, A con-PORATION OF NEW JERSEY VALVE FOR ROCK DRILLS Application filed September7, 1928 Serial No. 304,560.

This invention relates to rock drills, but more particularly to adistributing valve for fluid actuate-d rock drills of the hammer type.

The object of the invention is to obtain a light weight and durablevalve capable of a quick and positive action for distributing thepressure fluid to the ends of the rock drill cylinder.

Other objects will be in part obvious and in part pointedouthereinafter.

In the accompanying drawings illustrating the invention and in whichsimilar reference characters refer to similar parts,

Figure 1 is a sectional elevation of a rock drill equipped with a valveconstructed in accordance with the practice of the invention,

Figure 2 is a transverse view taken through Figure 1 on the line 22looking in the direction indicatedby the arrows, and

Figure 3 is aview similar to Figure 1 showing a modification of theinvention.

Referring to the drawings, the invention is shown embodied in a rockdrill A having a cylinder B in which is disposed a reciprocatory hammerpiston C. The cylinder B is provided with a free exhaust port Dcontrolled by the piston C In the front end of the cylinder B is a frontcylinder washer E having a bore F to slidably receive an extension G ofthe piston C. 1

"In order to obtain a step by step rotary movement of the workingimplement (not shown) against which the hammer piston C is intendedtodeliver its blows, the rock drill A is equipped with rotation mechanismcomprising a rifle bar H which interlocks slidably with the hammerpiston C. The rifle bar H has the usual head J in which are disposedspring pressed pawls K for engagement with a toothed ratchet L disposedin this instance in a bore 0 in the rearward end of the cylinder B. Therotation ratchet L forms a seat for a back head P and may be securedagainstrotation with respect to the cylinder B in any suitable manner.

The back head P may be conveniently secured to the cylinder B by meansof side bolts or their equivalent (not shown) and said back head has athrottle valve chamber Q to receive a throttle valve R whereby theadmission of pressure fluid into the drill A may be controlled. Thethrottlevalve R is preferably of the rotary type and has. a centralchamber S into which pressure fluid from a suitable source: of supplymay be introduced. In the wall of the throttle. valve R is'a portTadapted to register in the open position of the throttle valve with apassage U in the back head leading to a supply reservoir V in theinnermost surface of the back head.

In accordance with the present invention, the rock drill A is providedwith valve mechanism for efiecting the distribution of pres sure fluidto the ends of the cylinder. The

valve mechanism in this instance. is disposed in the front end of thebore and comprises a pair of ringplates W and X of the same width andwhich, when assembled, lie in face to face relationship. The plates areprovided with shallow recesses in their adjacent or abutting surfacesand between theinner and outer peripheral surfaces thereof to form avalve chamber Y of annular shape to receive a ringplate valve Z. s

Pressure fluid in this instance is conveyed to the valve chamber Ythrough supply passages 6 leading through the rotation ratchet L,through a plate a interposed between the rotation ratchet and the valvechest, and through the plates X and WV. Any suitable number of supplypassages may be provided for this purpose and'preferably each supplypassage is provided with a pair of ports d and e. The ports cl affordcommunication between the supply passages b andthe rearward end of thevalve chamber Y, and the ports e afford communication between the supplypassages b and the forward end of the valve chamber Y. For the bestoperation of the drill, the ports d and e are'preferably of somewhatsmaller cross sectional area than the supply passages so that thepressure fluid flowing into the ends of the" valve chambe will besomewhat restricted.

' The admission of pressure fluid to the rear ward end of the cylinderis effected through rearward inlet passages j which lead from v ward endof the cylinder. In like manner inlet passages g are formed in the plateW and in the cylinder 13 to lead from the front end of the valve chamberY to the front end of the cylinder B.

The plates W and X are each provided with a bore h of substantially thesame diameter as the piston chamber j in which the piston C is disposedand said bore 7t forms a continuation of the piston chamber j.

The operation of the device is as follows: With the throttle valve R inthe open position illustrated, pressure fluid will flow through thepassage U into the supply reservoir V from thence the pressure fluidflows through the supply passages b and through the ports at and 6. Withthe valve Z in the forwardmost position illustrated only an outerportion of the forward surface of the valve will be exposed to pressurefluid. At the same time pressure fluid will flow from the ports (Z overthe rearward surface of the valve Z and through the inlet passages finto the rearward end of the piston chamber 3' to drive the piston Cforwardly. Inasmuch that the entire rearward surface of the valve is exposed to pressure fluid, such pressure will predominate over that actingagainst the forward surface of the valve and the valve will therefore befirmly held against the front end of the valve chamber Y.

As the piston C travels in a forwardly direction, the exhaust port Dwill be covered thereby. The air in the front end of the pis ton chamberwill then be compressed by the piston and such compression flowingthrough the inlet passages 9 will act against the front surface of thevalve Z. These pressures acting against the front surfaces of the valve,however, are not sufficient to overcome that acting against the rearwardend of the valve until the piston C uncovers the exhaust port D. Thisoccurs shortly prior to the delivery of the blow of the piston againstthe working implement and causes an abrupt drop in pressure on therearward surface of the valve Z. -When this drop in pressure takesplace, the compression and the live pressure fluid acting against theforward surface of the valve Z will actuate the valve against therearward end of the valve chamber Y.

With the valve in the position described, pressure fluid will flowthrough the ports 6 into the front end of the valve chamber Y, thencethrough the inlet passages g into the front end of the piston chamber jto return the piston C to its initial position. During the rearwardstroke of the piston air will also be compressed in the piston chamberand such compression will flow through the inlet passages f to actagainst the rearward surface of the valve Z tending to throw the valveforwardly. In the rearward position of the valve, the outer portion ofthe rearward surface of the valve will also be exposed to pressure fluidand after the piston C uncovers the free exhaust port D, the drop inpressure on the forward surface of the valve Q will enable thecompression and the live air acting against the rearward surface of thevalve to throw said valve to its initial position.

Owing to the fact that the ports cl and e are of small cross sectionalarea, the flow of pressure fluid to the valve chamber will be somewhatrestricted so that after the free exhaust port D is uncovered by thepiston, the valve Z may be readily thrown by the compression and thelive air in the manner described before suflicient pressure may be builton the opposite surface of the valve to im pede the movement of thevalve.

In the modification illustrated in Figure 3, the valve chest designatedgenerally by is disposed in a bore 0 in the rearward end of the cylinderB. The valve chest 7:: comprises a pair of plates 79 and The plate 9 isdisposed in the forward end of the bore 0 while the plate p is seated onthe rearward end of the plate 9 and in turn acts as a seat for therotation ratchet L and the head J of the rifle bar and also serves as aclosure for the rearward end of the piston chamber In this form ofconstruction, a valve chamber o" in the form of an annular grooveopening from the rearward end of the plate 9 is formed in said plate 9to receive a distributing valve 8 of ring shape.

In order to hold the weight of the valve 8 to a minimum, said valve isprovided on its inner surface with a groove 2? thus forming innerlateral flanges u at the ends of the valve to engage with their innerperipheries the innermost surface 4) of the valve chamber for guidingthe valve. On the outer periphery r of the valve and intermediate theends thereof is a lateral flange 'w adapted to slide with its outersurface against the outermost surface w of the valve chamber 1".

In this modification, as in the modification previously described,pressure fluid is conveyed from the supply reservoir V by the supplypassages b and flows from said supply passages 6 through the ports d and6 into the valve chamber r. The ports d and e are arranged on oppositesides of the valve flange w and so disposed that they will not becovered at any time by said flange and pressure fluid may thereforeconstantly flow into the valve chamber 1" to expose both sides of theflange 'w to pressure fluid. The rearward inlet passages 9 also leaddirectly from the rearward end of the valve chamber 7* to thecorresponding end of the piston chamber 7' and the inlet passages 9 leadfrom the front end of the valve chamber 7" to the corresponding end ofthe piston chamber.

The operation of this modified form of the invention is similar to thatpreviously described and the valve differs principally from theconstruction previously described in that "it has an additional guidingsurface on its inner surface to assure against tilting of the valve inthe valve chamber.

We claim:

1. In a fluid actuated rock drill, the combination of a cylinder and apiston, an exhaust port for the cylinder controlled by the piston, avalve chest in the cylinder comprising a pair of ring plates arranged incontacting face to face relationship and having bores to form acontinuation of the cylinder, an annular valve chamber in the valvechest, inlet passages leading from the ends of the valve chamber to theends of the cylinder, a supply passage leading from a source toconstantly supply pressure fluid to both ends of the valve chamber, andan annular plate valve reciprocable in the valve chamber to controlcommunication between the supply and inlet passages.

2. In a fluid actuated rock drill, the combination of a cylinder and apiston, an exhaust port for the cylinder, a valve chest in the end ofthe cylinder comprising a pair of ring plates arranged in face to facerelation ship and having shallow recesses wholly within adjacent facesto form an annular valve chamber, inlet passages leading from the endsof the valve chamberto corresponding ends of the cylinder, a ring platevalve in the valve chamber controlling the inlet passages, a bore in theplates forming a continuation of the cylinder, supply passages in thevalve chest leading from a source of pressure fluid supply to conveypressure fluid to the valve chamber, and ports leading from the supplypassages to the ends of the valve chamber to constant-1y expose bothends of the valve to pressure fluid, said ports being of smaller crosssectional area than the supply passages to restrict the flow of pressureinto the ends of the valve chamber.

In testimony whereof we have signed this specification.

WILLIAM A. SMITH, SR. WILLIAM A. SMITH, JR.

